I always took it to mean to that she (his wife/romantic partner and soulmate) has passed away, and so the only place he sees her now is in his dreams, hence the line "Deep in a dream you'll always be, till the end of time". He also feels that she is the only one he will ever love, and so now he is alone for the rest of his life because no one could ever take her place. He thinks about her all the time, and when he wakes from his dreams, he imagines her next to him again, and feels deeply sad when he realizes she isn't. Whenever he's alone, she's all he sees. She's like an apparition that now haunts his dreams and memories, (haunts in a positive way, not in a bad way), the image at end of the music video portrays that very well. The woman is wearing a cape and a hood, and then as she turns and walks away she disappears. There's also a scene where her reflection is in the water, and when he puts his hand in the water, the reflection is gone. That is how the narrator sees her now...that she is always with him...but at the same time she isn't, because she's not in this world anymore. "Save all your love, save your love for me, don't turn your back on me..." basically means that he will never forget her, so he is telling her to never forget him wherever she has gone to, because he believes they will be together again and their love can never end, only go from one life to another.
I always took it to mean to that she (his wife/romantic partner and soulmate) has passed away, and so the only place he sees her now is in his dreams, hence the line "Deep in a dream you'll always be, till the end of time". He also feels that she is the only one he will ever love, and so now he is alone for the rest of his life because no one could ever take her place. He thinks about her all the time, and when he wakes from his dreams, he imagines her next to him again, and feels deeply sad when he realizes she isn't. Whenever he's alone, she's all he sees. She's like an apparition that now haunts his dreams and memories, (haunts in a positive way, not in a bad way), the image at end of the music video portrays that very well. The woman is wearing a cape and a hood, and then as she turns and walks away she disappears. There's also a scene where her reflection is in the water, and when he puts his hand in the water, the reflection is gone. That is how the narrator sees her now...that she is always with him...but at the same time she isn't, because she's not in this world anymore. "Save all your love, save your love for me, don't turn your back on me..." basically means that he will never forget her, so he is telling her to never forget him wherever she has gone to, because he believes they will be together again and their love can never end, only go from one life to another.